Urinary catheters are the most commonly used biomedical device, with approximately one in every five patients admitted to an acute care hospital receiving an indwelling catheter; the rate of catheter use is even higher among Medicare patients. Foley catheters are soft, plastic or rubber tubes that are placed transurethrally into the bladder to provide continuous drainage and relief when there is urinary retention, to monitor urine output for critically ill patients, to manage urination during surgery, and to provide end-of-life care. Foley catheters are commonly placed in hospital settings (emergency rooms, wards, intensive care units (ICUs), and operating rooms), urology and gynecology clinic settings, and in nursing homes. Foley catheters are recommended in the following situations: when urine is blocked due to bladder stones, blood clots in the urine, or narrowing of the urethra; during surgery of the prostate gland or in the genital area, such as a hip fracture repair or hysterectomy; after injury to the nerves of the bladder; spinal cord injury; when a condition impairs one's mental function, such as dementia; and when medications are taken that impair the ability of one's bladder muscles to squeeze, which causes urine to remain stuck in the bladder. Intermittent straight catheters (ISCs) are catheters that are commonly used in females with chronic bladder emptying issues due to neurologic conditions (such as multiple sclerosis) and pelvic floor muscle disorders. ISCs are inserted to drain the bladder, then immediately removed. Both indwelling Foley catheters and ISCs are associated with an increased rate of infection, and are placed using the same sterile procedure by clinicians in hospitalized and ambulatory patients to reduce the risk of introducing bacteria into the bladder during the placement procedure.
Certain conditions can make it quite difficult to part the labia of the female genitalia for sterile insertion of a urinary catheter. For example, it is not uncommon for the labia to be much thicker than normal, as much as 10 cm, in women with morbid obesity. Women who are bed bound and who must chronically lie on one side of their body can develop asymmetric labia due to dependent edema (i.e., swelling) in the inferior labia due to poor lymphatic drainage. Yet others have congenital asymmetry or anasarca (i.e., severe swelling). All of these conditions can make it more difficult to avoid contamination of a sterile catheter.
One of the primary complications that arise from the procedure of Foley catheter placement is the introduction of bacteria to the patient in either the bladder or mucosal membranes and blood stream, resulting in catheter-associated urinary tract infection. Catheter-associated urinary tract infection (CAUTI) is the most frequent healthcare-associated infection in the United States. Although most cases of bacteriuria are asymptomatic and resolve spontaneously once the catheter is removed, as many as 30% of patients with catheter-associated bacteriuria will develop symptom-related urinary tract infections requiring treatment. Additionally, the most clinically important adverse outcome associated with bacteriuria is urinary tract-related bacteremia. Bacteremia, or sepsis, is a highly morbid and costly complication associated with hospitalization and can increase hospital length of stay, or require hospital readmissions in the event a patient has been discharged, the costs for which insurers are increasingly resistant to reimburse.
For the above-mentioned reasons, the placement of Foley catheters using sterile (aseptic) techniques is imperative. Unfortunately, it is extremely challenging to maintain sterility throughout the multi-step procedure required for placement, particularly in females. Maintaining sterility during catheter placement in women is difficult due to the anatomic location of the female urethra and the need for retraction of the external female genitalia (vulva) in conjunction with common medical comorbidities such as obesity, edema, osteoarthritis and acute medical conditions such as altered mental status. Although various technologies have been employed to reduce the risks and associated complications of indwelling urinary catheters, such as bladder irrigation and antibiotic-coated catheters, there is still a need to improve the sterility of catheter placement.